Tăng cây thuộc tính: Xóa một nút

Question

Làm cách nào bạn xóa nút khỏi cây thuộc tính tăng xml?

Tôi có một tài liệu như thế này:

<folders> 
    <folder>some/folder</folder> 
    <folder>some/folder</folder> 
    <folder>some/folder</folder> 
</folders> 

Tôi biết làm thế nào để itereate và in tất cả các thư mục, nhưng làm thế nào tôi sẽ loại bỏ một trong các mục và lưu xml trở lại?

Answer 1

Vâng, tôi đã làm nó theo cách này:

void Backups::removeGeneric(const std::string key, const std::string value) 
{ 
    boost::property_tree::ptree pt; 
    boost::property_tree::xml_parser::read_xml(Backups::getBackupFile(), pt); 

    bool remove = true; 

    try { 
     pt.get_child(key); 
    } 
    catch(boost::exception &ex) 
    { 
     std::cout << "There is nothing to remove." << std::endl; 
     remove = false; 
    } 

    if(remove) 
    { 
     bool exists = false; 

     boost::property_tree::ptree newPt; 

     BOOST_FOREACH(boost::property_tree::ptree::value_type &v, pt.get_child(key)) 
     { 
      if(v.second.data() != value) 
       newPt.add("scheme", v.second.data()); 

      if(v.second.data() == value) 
       exists = true; 
     } 

     if(exists) 
     { 
      pt.put_child(key, newPt); 
      boost::property_tree::xml_parser::write_xml(Backups::getBackupFile(), pt); 

      std::cout << value << " was removed." << std::endl; 
     } 
     else 
      std::cout << value << " is not added." << std::endl; 
    } 
} 

Answer 2

void Backups::removeGeneric(const std::string key, const std::string value) 
{ 
    typedef boost::property_tree::ptree Tree; 

    Tree pt; 
    boost::property_tree::xml_parser::read_xml(Backups::getBackupFile(), pt); 

    std::pair< Tree::assoc_iterator, Tree::assoc_iterator> range = pt.equal_range(key); 
    if(range.first == pt.not_found()) 
    { 
     std::cout << "There is nothing to remove." << std::endl; 
    } 
    else 
    { 
     bool removed = false; 

     do 
     { 
      if(assoc_i->second.data() == value) { 
       Tree::iterator i = pt.to_iterator(assoc_i); 
       pt.erase(i); 
       removed = true; 
       // not sure if this is completely necessary - trying 
       // to guard against invalidating the iterator 
       // via erase - if removed, remember to ++i! 
       range = pt.equal_range(key); 
       i = range.first; 
      } 
      else 
       ++i; 
     } while(i != pt.not_found()); 

     if(removed) 
     { 
             boost::property_tree::xml_parser::write_xml(Backups::getBackupFile(), pt); 
      std::cout << value << " was removed." << std::endl; 
     } 
     else 
      std::cout << value << " is not added." << std::endl; 
    } 
} 

Answer 3

tôi có lẽ sẽ cố gắng:

boost::property_tree::ptree pt; 

pt.erase(key); 

Answer 4

// Recursively erase nodes 
    void prune_nodes(ptree& Prop_tree, const char* Node_name) 
    { 
     ptree::iterator Root = Prop_tree.begin(); // Node iterator 
     ptree::iterator End = Prop_tree.end(); // Stop sentinel 
     // Loop through current 'Root-Level' 
     for(Root; Root != End; Root++) 
     { 
      Root->second.erase(Node_name); // Erase nodes in current 'Root-Level' sub-tree 
      prune_nodes(Root->second, Node_name); // Recurse using current sub-tree as next call's ptree 
     } 
    }